Can't copy Firefox profile from old system to new system


still did not get the old browser settings available when I uninstalled and then re-installed Firefox 106.0.1
That is a very old version, is there a good reason you're using it? The current version is 134.0.1.
Version 106.0.1, first offered to Release channel users on October 20, 2022

Old system is Win 10 2H22, if that matters. New system is 23H2 22631.4602 ... I copied all the folders from the old folder into Mozilla Profiles.....
The thing about Firefox profiles is that they are version-specific. You can take an older profile and copy it to the profile folder for a newer version of Firefox, it will upgrade the profile when it first opens it.

What you cannot do is copy a profile from a newer version to an older one. An older version of Firefox cannot understand the changes to the profile made by a newer version of Firefox.

What version of Firefox was on the old machine you copied the profile from?
 

My Computers My Computers

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    Windows 11 HomeAMD Athlon Silver 3050U8GBRadeon Graphics
    OS
    Windows 11 Home
    Computer type
    Laptop
    Manufacturer/Model
    Acer Aspire 3 A315-23-R9VY
    CPU
    AMD Athlon Silver 3050U
    Memory
    8GB
    Graphics Card(s)
    Radeon Graphics
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    laptop screen
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    1TB Samsung EVO 870 SSD (from April 2026: 250GB EVO 850)
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    Edge, Firefox
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    Defender
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    fully 'Windows 11 ready' laptop. Windows 10 C: partition migrated from my old unsupported 'main machine' then upgraded to 11. A test migration ran Insider builds for 2 months. When 11 was released on 5th October 2021 it was re-imaged back to 10 and was offered the upgrade in Windows Update on 20th October. Windows Update offered the 22H2 Feature Update on 20th September 2022. It got the 23H2 Feature Update on 4th November 2023 through Windows Update, 24H2 on 3rd October 2024 through Windows Update by setting the Target Release Version for 24H2, and 25H2 on 30th September 2025 through Windows Update by setting the Target Release Version for 25H2.

    UPDATE - 11 April 2026: due to mechanical deterioration this PC has been retired from active duty. The OS with all software and files has been migrated to my System Seven in 'Other systems' to carry on as my general purpose 'main machine'.
  • At a glance

    Windows 11 ProIntel® Core™ i5-520M8GB(integrated graphics) Intel HD Graphics
    Operating System
    Windows 11 Pro
    Computer type
    Laptop
    Manufacturer/Model
    Dell Latitude E4310
    CPU
    Intel® Core™ i5-520M
    Motherboard
    0T6M8G
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    8GB
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    (integrated graphics) Intel HD Graphics
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    1366x768
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    500GB Crucial MX500 SSD
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    Firefox, Edge
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    Defender
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    unsupported machine: Legacy bios, MBR, TPM 1.2, upgraded from W10 to W11 using W10/W11 hybrid install media workaround.

    In-place upgrade to 22H2 using ISO and a workaround.
    Feature Update to 23H2 by manually installing the Enablement Package.
    In-place upgrade to 24H2 using hybrid 23H2/24H2 install media.
    Upgraded to 25H2 by Enablement Package.

    Also running Insider Dev, and Canary builds and Windows 10 as native boot .vhdx.
  • My SYSTEM THREE is a Dell Latitude 5410, i7-10610U, 32GB RAM, 512GB NVMe ssd, supported device running Windows 11 Pro.

    My SYSTEM FOUR is a 2-in-1 convertible Lenovo Yoga 11e 20DA, Celeron N2930, 8GB RAM, 256GB ssd. Unsupported device: currently running Win10 Pro, plus Win11 Pro RTM and Insider Dev, Beta, and RP 24H2 as native boot vhdx.

    My SYSTEM FIVE is a Dell Latitude 3190 2-in-1, Pentium Silver N5030, 8GB RAM, 1TB NVMe ssd, supported device running Windows 11 Pro, plus Insider Beta, Dev, and Canary builds (and a few others) as a native boot .vhdx.

    My SYSTEM SIX is a Dell Latitude 5550, Core Ultra 7 165H, 64GB RAM, 1TB NVMe SSD, supported device, Windows 11 Pro 24H2, Hyper-V host machine. Updated to 25H2 on 30th September 2025.

    My SYSTEM SEVEN is a Lenovo Thinkpad T580, Intel Core i7-8650U, 16GB RAM, 512GB NVMe SSD + 2nd 512GB NVMe SSD, a supported device for Windows 11. This is my current general purpose 'main machine'. The installed Windows 11 Home from my System One has been migrated to this machine.
I copy the entire Mozilla folder to the Roaming folder.

C:\Users\xxxx\AppData\Roaming

I download the latest Firefox and then install as administrator.

100% success
 

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At a glance

windows 11 ,Ubuntu Cinnamon - for tinkering onlyIntel i51140016 GB0
OS
windows 11 ,Ubuntu Cinnamon - for tinkering only
Computer type
PC/Desktop
Manufacturer/Model
No Name - Assembled by a Compute shop in a Strip Mall.
CPU
Intel i511400
Motherboard
ASUS PRIME B560-PLUS motherboard
Memory
16 GB
Graphics Card(s)
0
Sound Card
0
Monitor(s) Displays
25 in BenQ
Screen Resolution
1920 x 1080
Hard Drives
9 SSDs 4 Nvme, 2 in M.2 slot and 2 in PCIE with adapter + 5 Sata. DVD drive
PSU
600w
Case
Antec- VSK4000E-U3 Mid Tower
Internet Speed
Bell pure fibre optic. 3 GB package. 6E Wireless adapter 750/500
Browser
Firefox, Microsoft Edge
Antivirus
Defender
That is a very old version, is there a good reason you're using it? The current version is 134.0.1.
Version 106.0.1, first offered to Release channel users on October 20, 2022


The thing about Firefox profiles is that they are version-specific. You can take an older profile and copy it to the profile folder for a newer version of Firefox, it will upgrade the profile when it first opens it.

What you cannot do is copy a profile from a newer version to an older one. An older version of Firefox cannot understand the changes to the profile made by a newer version of Firefox.

What version of Firefox was on the old machine you copied the profile from?
My mistake. New version is 136.0.1
 

My Computer My Computer

At a glance

Windows 11 2H25AMD 9900X64 GBAMD 9070 XT
OS
Windows 11 2H25
Computer type
PC/Desktop
Manufacturer/Model
DIY
CPU
AMD 9900X
Motherboard
MSI X870E Carbon
Memory
64 GB
Graphics Card(s)
AMD 9070 XT
Sound Card
built-in
Monitor(s) Displays
Dell 24"
Hard Drives
Sabrent 1 TB NVMe, 4 x SSD (need to check models), 4 x 3.5" HDD, 8-16 TB, all WD
PSU
Seasonic 850
Case
Fractal Design North XL (which I likw)
Cooling
Corsair AIO for CPU, fans for case
Keyboard
Das Keyboard 4
Mouse
Corsair M65 (white)
Internet Speed
1 TB download
Browser
Firefox
Antivirus
Bitdefender
Other Info
Also have Lenovo T14S laptop (me) and Lenovo Slim 71 (wife)
My mistake. New version is 136.0.1
134.0.1 is the latest FireFox release.
136.0a1 was a nightly build from 1/6/2025

There is no 136.0.1 build yet.

FWIW making a Mozilla FireFox profile account and using profile SYNC is the way to go IMHO
 

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    Win11 25H2 26200.7623Intel XEON W-2245 8c/16t128GB DDR4-2933 ECCNvidia Quadro K4200
    OS
    Win11 25H2 26200.7623
    Computer type
    PC/Desktop
    Manufacturer/Model
    Lenovo P520
    CPU
    Intel XEON W-2245 8c/16t
    Memory
    128GB DDR4-2933 ECC
    Graphics Card(s)
    Nvidia Quadro K4200
    Sound Card
    Bultin
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    LCD 24in
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    1920x1200
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    1TB SSD system, 16TB data 3.5in HDD, 16TB backup 3.5in HDD
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    900W
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    Air
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    1Gb
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    Firefox & Chrome
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    MalwareBytes
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    Win10 22H2Intel Core i7-3520m16GBintegrated CPU graphics
    Operating System
    Win10 22H2
    Computer type
    Laptop
    Manufacturer/Model
    Lenovo T530
    CPU
    Intel Core i7-3520m
    Memory
    16GB
    Graphics card(s)
    integrated CPU graphics
    Hard Drives
    1TB SSD
    Internet Speed
    1Gb
    Browser
    Fiefox & Chrome
    Antivirus
    Malwarebytes
134.0.1 is the latest FireFox release.
136.0a1 was a nightly build from 1/6/2025

There is no 136.0.1 build yet.

FWIW making a Mozilla FireFox profile account and using profile SYNC is the way to go IMHO
OK. I'm an idiot. Trying to get too many things done at the same time, not paying enough attention to any one item.
 

My Computer My Computer

At a glance

Windows 11 2H25AMD 9900X64 GBAMD 9070 XT
OS
Windows 11 2H25
Computer type
PC/Desktop
Manufacturer/Model
DIY
CPU
AMD 9900X
Motherboard
MSI X870E Carbon
Memory
64 GB
Graphics Card(s)
AMD 9070 XT
Sound Card
built-in
Monitor(s) Displays
Dell 24"
Hard Drives
Sabrent 1 TB NVMe, 4 x SSD (need to check models), 4 x 3.5" HDD, 8-16 TB, all WD
PSU
Seasonic 850
Case
Fractal Design North XL (which I likw)
Cooling
Corsair AIO for CPU, fans for case
Keyboard
Das Keyboard 4
Mouse
Corsair M65 (white)
Internet Speed
1 TB download
Browser
Firefox
Antivirus
Bitdefender
Other Info
Also have Lenovo T14S laptop (me) and Lenovo Slim 71 (wife)
Guys,

I'm, happy to say that I have finally, finally succeeded in transferring the old FF profile to the new system. I think I sort of blundered into success, to be totally, totally honest. But my wife is happy and that is what counts the most to me.:cool:
 

My Computer My Computer

At a glance

Windows 11 2H25AMD 9900X64 GBAMD 9070 XT
OS
Windows 11 2H25
Computer type
PC/Desktop
Manufacturer/Model
DIY
CPU
AMD 9900X
Motherboard
MSI X870E Carbon
Memory
64 GB
Graphics Card(s)
AMD 9070 XT
Sound Card
built-in
Monitor(s) Displays
Dell 24"
Hard Drives
Sabrent 1 TB NVMe, 4 x SSD (need to check models), 4 x 3.5" HDD, 8-16 TB, all WD
PSU
Seasonic 850
Case
Fractal Design North XL (which I likw)
Cooling
Corsair AIO for CPU, fans for case
Keyboard
Das Keyboard 4
Mouse
Corsair M65 (white)
Internet Speed
1 TB download
Browser
Firefox
Antivirus
Bitdefender
Other Info
Also have Lenovo T14S laptop (me) and Lenovo Slim 71 (wife)
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